The present invention relates to a ridge vent for roofs, and in particular, to a ridge vent for use on asphalt shingle or other composition roofs, preferably having a pitch of at least 2/12.
It has been known to ventilate attics under gable roofs by running a vent along the roof ridge. Such vents are created during construction by sizing the uppermost row of sheathing panels to leave an open slot running along the ridge essentially the length of the roof. The slot creates effective heat ventilation by convection flow and suction caused by wind across the roof ridge. For retrofitting existing roofs, the slot can be cut along the roof ridge.
Soffit ventilators are perforated or louvered openings located along the eaves of an overhanging roof. The vents allow fresh ambient air to flow into the attic to equalize attic temperature and pressure with the outside. This equalization inhibits moisture from condensing on insulation and wood roofing materials which causes mildew and rot, prevents build-up of ice dams which could buckle shingles and gutters, and reduces air-conditioning costs when hot attic air is replaced by cooler ambient air.
A soffit ventilation system works in conjunction with a ridge vent to provide passive ventilation. As hot stale air is withdrawn from the ridge slot vent by convection and/or wind suction, it is replaced by fresh ambient air through the soffit vents.
One known ridge vent that has proven to be very successful is described in the inventor's prior U.S. Pat. No. 5,167,579. This roof vent is formed using a non-woven synthetic fiber mat having randomly aligned fibers located over a vent slot at the roof ridge. Cap shingles are then installed over the non-woven synthetic fiber mat. The synthetic fiber mat allows for air flow through the slot at the roof ridge, while preventing the ingress of moisture and debris. However, this type of ridge vent does not always form a clean ridge line due to the material becoming rounded as it extends over the slot and partially down on each side of the roof.